As a method for mounting a chip component such as an LED on a circuit board, a method in which the chip component is flip-chip mounted using an anisotropic conductive adhesive in which conductive particles are dispersed in an epoxy-based adhesive has been widely adopted (for example, refer to Patent Literatures 1 and 2). According to this method, since the conductive particles contained in the anisotropic conductive adhesive electrically connect the chip component to the circuit board, it is possible to reduce time required for a connection process and improve production efficiency.
Currently, white light emitting devices using an LED element having a fluorescent layer are in the mainstream of lighting devices, and various techniques have been developed. For example, there is a technique in which solder is used for bumps, and an LED element is connected to a wiring board by reflow soldering (Patent Literatures 3 and 4, and the like). However, the reflow soldering by thermosonic bonding or the like has a problem that exfoliation may occur between a body semiconductor chip configured to emit light and a fluorescent layer configured to change the emitted light into white light. When the body semiconductor chip is fixed to the wiring board only by soldering, the body semiconductor chip may exfoliate from the wiring board.
As measures against this, there may be mentioned a method in which flux is applied to a surface of the wiring board, a method in which a weight is applied during the reflow soldering, and the like. However, there are problems that the fluorescent layer tends to exfoliate during cleaning of the flux, and the application of the weight under high temperature collapses the fluorescent layer.